1. Field
The disclosure herein relates to printed circuit boards, and more particularly, insulating layers for use with rigid printed circuit boards.
2. Description of the Related Art
Printed circuit boards (PCB) comprise one or more layers of electrically conductive material such as copper and one or more electrically insulating layers such as dielectrics. Multilayer PCBs typically comprise two or more inner and/or surface conductive layers formed over and separated by a plurality of insulating layers with holes, vias, and through holes providing electrical connection between the various inner conductive layers and other inner conductive layers and/or the surface conductive layers.
Several aspects of the PCB manufacturing and assembly processes subject PCB components to strain or stress (e.g., mechanical, thermal, physical, chemical, and the like). For example, manufacturing exposes PCBs to a range of temperatures, including high soldering temperatures which have increased even more in response to the industry's recent adoption of lead-free processes. Strain can cause defects in components, resulting in electrical and/or mechanical failure. For example, thermal strain arising from increasing temperatures can cause cracks in the PCB components, including pad cratering, a type of crack typically occurring in insulating layers that engage surface conductive layers. Various embodiments disclosed herein contemplate certain more stable and damage-resistant PCB components for use with rigid PCBs that may substantially increase the yield of rigid PCBs while possibly reducing defects such as voids and cracks and increasing the structural integrity of the rigid PCBs and portions of rigid PCBs such as junctions between insulating layers and surface conductive layers.